The Astrophysical Journal Letters最新文献_第6页

Protostellar Disk Formation Regimes: Angular Momentum Conservation versus Magnetic Braking 原恒星盘形成机制：角动量守恒与磁制动

The Astrophysical Journal Letters Pub Date : 2024-09-08 DOI: 10.3847/2041-8213/ad7263

Hsi-Wei Yen and Yueh-Ning Lee

{"title":"Protostellar Disk Formation Regimes: Angular Momentum Conservation versus Magnetic Braking","authors":"Hsi-Wei Yen and Yueh-Ning Lee","doi":"10.3847/2041-8213/ad7263","DOIUrl":"https://doi.org/10.3847/2041-8213/ad7263","url":null,"abstract":"Protostellar disks around young protostars exhibit diverse properties, with their radii ranging from less than ten to several hundred astronomical units. To investigate the mechanisms shaping this disk radius distribution, we compiled a sample of 27 Class 0 and I single protostars with resolved disks and dynamically determined protostellar masses from the literature. Additionally, we derived the radial profile of the rotational-to-gravitational-energy ratio in dense cores from the observed specific angular momentum profiles in the literature. Using these observed protostellar masses and rotational energy profile, we computed theoretical disk radii from the hydrodynamic and nonideal magnetohydrodynamic (MHD) models in Y.-N. Lee et al. and generated synthetic samples to compare with the observations. In our theoretical model, the disk radii are determined by hydrodynamics when the central protostar+disk mass is low. After the protostars and disks grow and exceed certain masses, the disk radii become regulated by magnetic braking and nonideal MHD effects. The synthetic disk radius distribution from this model matches well with the observations. This result suggests that hydrodynamics and nonideal MHD can be dominant in different mass regimes (or evolutionary stages), depending on the rotational energy and protostar+disk mass. This model naturally explains the rarity of large (>100 au) disks and the presence of very small (<10 au) disks. It also predicts that the majority of protostellar disks have radii of a few tens of astronomical units, as observed.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142160646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An Accreting Supermassive Black Hole Buried in a Faint Dwarf Galaxy 埋藏在一个微弱矮星系中的吸积型超大质量黑洞

The Astrophysical Journal Letters Pub Date : 2024-09-05 DOI: 10.3847/2041-8213/ad7388

Abhishek Paswan, Mousumi Das and K Rubinur

{"title":"An Accreting Supermassive Black Hole Buried in a Faint Dwarf Galaxy","authors":"Abhishek Paswan, Mousumi Das and K Rubinur","doi":"10.3847/2041-8213/ad7388","DOIUrl":"https://doi.org/10.3847/2041-8213/ad7388","url":null,"abstract":"In the last decade, there have been several discoveries of active galactic nuclei (AGN) in dwarf galaxies including an AGN in an ultracompact dwarf galaxy with a black hole mass >106M⊙. However, finding a supermassive black hole (SMBH) in a dwarf low surface brightness (LSB) galaxy is rare. We report the discovery of a Seyfert type 2 class AGN that is associated with a nuclear SMBH of mass ∼6.5 × 106M⊙ in a dwarf LSB galaxy (μ0,r > 23.8 mag arcsec−2) that we denote by MJ0818+2257. The galaxy was previously thought to be an outlying emission blob around the large spiral galaxy LEDA 1678924. In our current analysis, which includes the detection of the optical counterpart of MJ0818+2257, we study its ionized gas kinematics and find that the dynamical mass within the ionized gas disk is ∼5.3 × 109M⊙. This is comparable to its stellar mass, which is ∼3 × 109M⊙, and suggests that MJ0818+2257 is moderately dark matter dominated within the stellar disk. The SMBH-mass-to-galaxy-stellar-mass ratio is MBH/M(*) > 0.022, which is high compared to disk galaxies. Our detection of an SMBH in a bulgeless LSB dwarf galaxy raises questions about the growth of SMBHs in low-luminosity galaxies and suggests the possibility of detecting heavy seed black holes from early epochs in LSB dwarf galaxies in the low-redshift Universe.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142144089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Unveiling the Central Engine of Core-collapse Supernovae in the Local Universe: Neutron Star or Black Hole? 揭开局域宇宙中核心坍缩超新星的中心引擎：中子星还是黑洞？

The Astrophysical Journal Letters Pub Date : 2024-09-05 DOI: 10.3847/2041-8213/ad710f

Maurice H. P. M. van Putten, Maryam Aghaei Abchouyeh and Massimo Della Valle

{"title":"Unveiling the Central Engine of Core-collapse Supernovae in the Local Universe: Neutron Star or Black Hole?","authors":"Maurice H. P. M. van Putten, Maryam Aghaei Abchouyeh and Massimo Della Valle","doi":"10.3847/2041-8213/ad710f","DOIUrl":"https://doi.org/10.3847/2041-8213/ad710f","url":null,"abstract":"The physical trigger powering supernovae following the core collapse of massive stars is believed to involve a neutron star (NS) or a black hole (BH), depending largely on progenitor mass. A potentially distinct signature is long-duration gravitational-wave (GW) bursts from BH central engines by their ample energy reservoir EJ in angular momentum, far more so than an NS can provide. A natural catalyst for this radiation is surrounding high-density matter in the form of a nonaxisymmetric disk or torus. Here, we derive a detailed prospect on LIGO–Virgo–KAGRA probes of core-collapse supernovae during the present observational run O4 based on their event rate, an association with normal long gamma-ray bursts (GRBs) and mass scaling of GW170817B/GRB170817A. For BH central engines of mass M, GW170817B predicts a descending GW chirp of energy at frequency , where M0 ≃ 2.8 M⊙. For a few tens of events per year well into the Local Universe within 50–100 Mpc, probes at the detector-limited sensitivity are expected to break the degeneracy between their NS or BH central engines by GW calorimetry.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142142719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Relation between the keV–MeV and TeV Emission of GRB 221009A and Its Implications GRB 221009A 的 keV-MeV 和 TeV 发射之间的关系及其影响

The Astrophysical Journal Letters Pub Date : 2024-09-05 DOI: 10.3847/2041-8213/ad6df8

Yan-Qiu Zhang, Haoxiang Lin, Shao-Lin Xiong, Zhuo Li, Ming-Yu Ge, Chen-Wei Wang, Shu-Xu Yi, Zhen Zhang, Shuang-Nan Zhang, Li-Ming Song, Chao Zheng, Wang-Chen Xue, Jia-Cong Liu, Wen-Jun Tan, Yue Wang and Wen-Long Zhang

{"title":"Relation between the keV–MeV and TeV Emission of GRB 221009A and Its Implications","authors":"Yan-Qiu Zhang, Haoxiang Lin, Shao-Lin Xiong, Zhuo Li, Ming-Yu Ge, Chen-Wei Wang, Shu-Xu Yi, Zhen Zhang, Shuang-Nan Zhang, Li-Ming Song, Chao Zheng, Wang-Chen Xue, Jia-Cong Liu, Wen-Jun Tan, Yue Wang and Wen-Long Zhang","doi":"10.3847/2041-8213/ad6df8","DOIUrl":"https://doi.org/10.3847/2041-8213/ad6df8","url":null,"abstract":"Gamma-ray bursts (GRBs) are believed to launch relativistic jets, which generate prompt emission by internal processes, and produce long-lasting afterglows by driving external shocks into the surrounding medium. However, how the jet powers the external shock is poorly known. The unprecedented observations of the keV–MeV emission with Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor and the TeV emission with LHAASO of the brightest-of-all-time GRB 221009A offer a great opportunity to study the prompt-to-afterglow transition and the impact of jet on the early dynamics of external shock. In this Letter, we find that the cumulative light curve of keV–MeV emission could well fit the rising stage of the TeV light curve of GRB 221009A, with a time delay, s, of TeV emission. Moreover, both the rapid increase in the initial stage and the excess from about Tref + 260 s to 270 s in the TeV light curve are tracking the light-curve bumps in the prompt keV–MeV emission. The close relation between the keV–MeV and TeV emission reveals the continuous energy injection into the external shock. Assuming an energy injection rate exactly following the keV–MeV flux of GRB 221009A, including the very early precursor, we build a continuous energy injection model where the jet Lorentz factor is derived from the TeV time delay, and the TeV data are well fitted, with the TeV excesses interpreted by inverse-Compton scatterings of the inner-coming prompt emission by the energetic electrons in external shock.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142144088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Irregular Moons Possibly Injected from the Outer Solar System by a Stellar Flyby 恒星飞越时可能从太阳系外注入的不规则卫星

The Astrophysical Journal Letters Pub Date : 2024-09-03 DOI: 10.3847/2041-8213/ad63a6

Susanne Pfalzner, Amith Govind and Frank W. Wagner

引用次数: 0

On the Correlation between Young Massive Star Clusters and Gamma-Ray Unassociated Sources 论年轻大质量星团与伽马射线非相关源之间的相关性

The Astrophysical Journal Letters Pub Date : 2024-09-02 DOI: 10.3847/2041-8213/ad7024

Giada Peron, Giovanni Morlino, Stefano Gabici, Elena Amato, Archana Purushothaman and Marcella Brusa

{"title":"On the Correlation between Young Massive Star Clusters and Gamma-Ray Unassociated Sources","authors":"Giada Peron, Giovanni Morlino, Stefano Gabici, Elena Amato, Archana Purushothaman and Marcella Brusa","doi":"10.3847/2041-8213/ad7024","DOIUrl":"https://doi.org/10.3847/2041-8213/ad7024","url":null,"abstract":"Star clusters (SCs) are potential cosmic-ray accelerators and therefore are expected to emit high-energy radiation. However, a clear detection of gamma-ray emission from this source class has only been possible for a handful of cases. This could in principle result from two different reasons: either detectable SCs are limited to a small fraction of the total number of Galactic SCs, or gamma-ray-emitting SCs are not recognized as such and therefore are listed in the ensemble of unidentified sources. In this Letter we investigate this latter scenario by comparing available catalogs of SCs and H ii regions, obtained from Gaia and Wide-field Infrared Survey Explorer observations, to the gamma-ray GeV and TeV catalogs built from Fermi Large Area Telescope (LAT), H.E.S.S., and LHAASO data. The significance of the correlation between catalogs is evaluated by comparing the results with simulations of synthetic populations. A strong correlation emerges between Fermi-LAT-unidentified sources and H ii regions that trace massive SCs in the earliest (≲1–2 Myr) phase of their life, where no supernova explosions have happened yet, confirming that winds of massive stars can alone accelerate particles and produce gamma-ray emission at least up to GeV energies. The association with TeV energy sources is less evident. Similarly, no significant association is found between Gaia SCs and GeV nor TeV sources. We ascribe this fact to the larger extension of these objects but also to an intrinsic bias in the Gaia selection toward SCs surrounded by a lower target gas density, which would otherwise hinder the detection in the optical wave band.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142130825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Sudden Polarization Angle Jumps of the Repeating Fast Radio Burst FRB 20201124A 重复快速射电暴 FRB 20201124A 的突然偏振角跃迁

The Astrophysical Journal Letters Pub Date : 2024-09-01 DOI: 10.3847/2041-8213/ad7023

J. R. Niu, W. Y. Wang, J. C. Jiang, Y. Qu, D. J. Zhou, W. W. Zhu, K. J. Lee, J. L. Han, B. Zhang, D. Li, S. Cao, Z. Y. Fang, Y. Feng, Q. Y. Fu, P. Jiang, W. C. Jing, J. Li, Y. Li, R. Luo, L. Q. Meng, C. C. Miao, X. L. Miao, C. H. Niu, Y. C. Pan, B. J. Wang, F. Y. Wang, H. Z. Wang, P. Wang, Q. Wu, Z. W. Wu, H. Xu, J. W. Xu, L. Xu, M. Y. Xue, Y. P. Yang, M. Yuan, Y. L. Yue, D. Zhao, C. F. Zhang, D. D. Zhang, J. S. Zhang, S. B. Zhang, Y. K. Zhang and Y. H. Zhu

{"title":"Sudden Polarization Angle Jumps of the Repeating Fast Radio Burst FRB 20201124A","authors":"J. R. Niu, W. Y. Wang, J. C. Jiang, Y. Qu, D. J. Zhou, W. W. Zhu, K. J. Lee, J. L. Han, B. Zhang, D. Li, S. Cao, Z. Y. Fang, Y. Feng, Q. Y. Fu, P. Jiang, W. C. Jing, J. Li, Y. Li, R. Luo, L. Q. Meng, C. C. Miao, X. L. Miao, C. H. Niu, Y. C. Pan, B. J. Wang, F. Y. Wang, H. Z. Wang, P. Wang, Q. Wu, Z. W. Wu, H. Xu, J. W. Xu, L. Xu, M. Y. Xue, Y. P. Yang, M. Yuan, Y. L. Yue, D. Zhao, C. F. Zhang, D. D. Zhang, J. S. Zhang, S. B. Zhang, Y. K. Zhang and Y. H. Zhu","doi":"10.3847/2041-8213/ad7023","DOIUrl":"https://doi.org/10.3847/2041-8213/ad7023","url":null,"abstract":"We report the first detection of polarization angle orthogonal jumps, a phenomenon previously only observed from radio pulsars, from a fast radio burst (FRB) source FRB 20201124A. We find three cases of orthogonal jumps in over 2000 bursts, all resembling those observed in pulsar single pulses. We propose that the jumps are due to the superposition of two orthogonal emission modes that could only be produced in a highly magnetized plasma, and they are caused by the line of sight sweeping across a rotating magnetosphere. The shortest jump timescale is of the order of 1 millisecond, which hints that the emission modes come from regions smaller than the light cylinder of most pulsars or magnetars. This discovery provides convincing evidence that FRB emission originates from the complex magnetosphere of a magnetar, suggesting an FRB emission mechanism that is analogous to radio pulsars despite a huge luminosity difference between two types of objects.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142123777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Close Encounters of Wide Binaries Induced by the Galactic Tide: Implications for Stellar Mergers and Gravitational-wave Sources 银河系潮汐诱发的宽双星近距离相遇：对恒星合并和引力波源的影响

The Astrophysical Journal Letters Pub Date : 2024-09-01 DOI: 10.3847/2041-8213/ad70bb

Jakob Stegmann, Alejandro Vigna-Gómez, Antti Rantala, Tom Wagg, Lorenz Zwick, Mathieu Renzo, Lieke A. C. van Son, Selma E. de Mink and Simon D. M. White

{"title":"Close Encounters of Wide Binaries Induced by the Galactic Tide: Implications for Stellar Mergers and Gravitational-wave Sources","authors":"Jakob Stegmann, Alejandro Vigna-Gómez, Antti Rantala, Tom Wagg, Lorenz Zwick, Mathieu Renzo, Lieke A. C. van Son, Selma E. de Mink and Simon D. M. White","doi":"10.3847/2041-8213/ad70bb","DOIUrl":"https://doi.org/10.3847/2041-8213/ad70bb","url":null,"abstract":"A substantial fraction of stars can be found in wide binaries with projected separations between ∼102 and 105 au. In the standard lore of binary physics, these would evolve as effectively single stars that remotely orbit one another on stationary Keplerian ellipses. However, embedded in their Galactic environment, the low binding energy of wide binaries makes them exceptionally prone to perturbations from the gravitational potential of the Milky Way and encounters with passing stars. Employing a fully relativistic N-body integration scheme, we study the impact of these perturbations on the orbital evolution of wide binaries along their trajectory through the Milky Way. Our analysis reveals that the torques exerted by the Galaxy can cause large-amplitude oscillations of the binary eccentricity to 1 − e ≲ 10−8. As a consequence, the wide binary members pass close to each other at periapsis, which, depending on the type of binary, potentially leads to a mass transfer or collision of stars or to an inspiral and subsequent merger of compact remnants due to gravitational-wave radiation. Based on a simulation of 105 wide binaries across the Galactic field, we find that this mechanism could significantly contribute to the rate of stellar collisions and binary black hole mergers as inferred from observations of luminous red novae and gravitational-wave events by LIGO/Virgo/Kagra. We conclude that the dynamics of wide binaries, despite their large mean separation, can give rise to extreme interactions between stars and compact remnants.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142123778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Neutron Star Kicks plus Rockets as a Mechanism for Forming Wide Low-eccentricity Neutron Star Binaries 中子星 "踢腿 "加 "火箭 "作为形成宽大的低偏心率中子星双星的机制

The Astrophysical Journal Letters Pub Date : 2024-08-29 DOI: 10.3847/2041-8213/ad6e77

Ryosuke Hirai, 遼介平井, Philipp Podsiadlowski, Alexander Heger, Hiroki Nagakura and 洋樹長倉

引用次数: 0

Delayed Emission from Luminous Blue Optical Transients in Black Hole Binary Systems 黑洞双星系统中蓝色发光瞬态的延迟发射

The Astrophysical Journal Letters Pub Date : 2024-08-29 DOI: 10.3847/2041-8213/ad70ba

Davide Lazzati, Rosalba Perna, Taeho Ryu and Katelyn Breivik

{"title":"Delayed Emission from Luminous Blue Optical Transients in Black Hole Binary Systems","authors":"Davide Lazzati, Rosalba Perna, Taeho Ryu and Katelyn Breivik","doi":"10.3847/2041-8213/ad70ba","DOIUrl":"https://doi.org/10.3847/2041-8213/ad70ba","url":null,"abstract":"At least three members of the recently identified class of fast luminous blue optical transients show evidence of late-time electromagnetic activity in great excess of what was predicted by an extrapolation of the early time emission. In particular, AT2022tsd displays fast, bright optical fluctuations approximately a month after the initial detection. Here we propose that these transients are produced by exploding stars in black hole binary systems and that the late-time activity is due to the accretion of clumpy ejecta onto the companion black hole. We derive the energetics and timescales involved, compute the emission spectrum, and discuss whether the ensuing emission is diffused or not in the remnant. We find that this model can explain the observed range of behaviors for reasonable ranges of the orbital separation and the ejecta velocity and clumpiness. Close separation and clumpy, high-velocity ejecta result in bright variable emission, as seen in AT2022tsd. A wider separation and smaller ejecta velocity, conversely, give rise to fairly constant emission at a lower luminosity. We suggest that high-cadence, simultaneous, panchromatic monitoring of future transients should be carried out to better understand the origin of the late emission and the role of binarity in the diversity of explosive stellar transients.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142100975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0